1. Field of the Invention
The present invention relates to the technical field of apparatus for producing hydrocarbons from one or more subsea wells.
2. Description of the Related Art
Operating subsea wells generally comprises a drilling phase during which the wellheads and other subsea installations on the sea floor are implemented, followed by a phase during which the permanent pipes from the sea floor to the sea surface are installed. For example, a wellhead may be situated at a depth greater than 500 meters (m), or indeed greater than 3,000 m. Production, i.e. commissioning, only begins after the arrival of a hydrocarbon collection and pretreatment vessel also known as a “Floating Production, Storage and Offloading” (FPSO) unit.
It is thus possible for a period of a few weeks to a few months to elapse between the end of the drilling phase and the start of production. A subsea hydrocarbon field can typically produce in the range 50,000 barrels of oil per day to 200,000 barrels of oil per day. The shortfall resulting from that period is thus particularly large, in particular since the investment for implementing subsea installations for producing hydrocarbons is considerable. Typically, the cost of developing an offshore field is several billion US dollars.